1. Field of Invention
This invention relates to weighted shafts used for exercising, strengthening and stretching muscles, so as to develop muscular memory and physical expertise at sports such as golf, tennis, baseball and others, while minimizing the shock and stress imposed on the muscles at the end of the swing.
2. Description of Prior Art
The idea of using isotonic and isometric resistance in the development of training regiments to help foster superior performance at games has been the goal of athletes and coaches for centuries.
Weighted shafts of various configurations have been devised by others to exercise and strengthen muscles by swinging them back and forth along a path similar to that a golf club, tennis racket, baseball bat and so forth. It has been demonstrated that by adding weight to the swing path during training, muscle performance is enhanced.
A search of the patent literature has revealed a number of sports swing exercise devices reaching back to U.S. Pat. No. 48,050 by Butler issued in June 1865. More current and thus more applicable patents, some employing as a key feature a weight swung on the end of a shaft, are as follows.
U.S. Pat. No. 3,743,297 (1973) involves an end-weighted shaft for golf swing practice whereby a ball is designed to "accommodate unsuitable and removable weights."
U.S. Pat. No. 4,213,614 (1980) involves a "combination weight attachment and golf club cover" whereby "lead pellets or other weighted materials are enclosed in the zippered bag to provide means for adjusting the attached weight to individual taste."
U.S. Pat. Nos. 4,444,396 (1984) and 4,602,788 (1986) by Wendt involve a shaft that is end-fitted to accept a "series of perforated discs weighing 1,2,4,8 and 16 ounces" whereby the user can weight the shaft according to his desired training resistance.
U.S. Pat. No. 5,209,481 (1993) employs a golf handle within a curved or L shaped member whereby an adjustable weight is attached to the lower arc and swung.
U.S. Pat. No. 5,121,925 (1992) is comprised of a weight at the end of a shaft with the end "thereof bent at about 22.05 degrees and on which rotatable off-center swing weights are mounted which enables a user to simulate the movements of a proper golf swing and which also exercises the muscles of a golfer making such a swing."
U.S. Pat. No. 5,249,803 (1993) involves a "shaft having a grip end and a head end, a weight disposed at the head end, and a link nonintegrally attaching the weight to the head end of the shaft."
U.S. Pat. No. 5,330,193 (1994) is for a device with a symmetrical end-weighted tapering shaft where the weights are "cylindrical members of different sizes."
U.S. Pat. No. 5,330,190 (1994) is another end-weighted golf trainer employing two tubes of polyvinylchloride that provide "limited resilience and flexibility."
In addition to end-weighted swing training devices, others using wind resistance in lieu of weights to increase the training effect have been invented, notably U.S. Pat. Nos. 5,002,275 (1991), 5,026,064 (1991) and 5,236,192 (1993).
U.S. Pat. No. 5,040,788 (1991) employs a stretchable cord the user attaches to a doorknob. U.S. Pat. No. 3,722,890 (1973) deals with a loop attached to a threaded eye bolt with a pair of lock nuts "between which a plurality of washers are clamped" and fits over a golf club head.
Two other patents that approximate a key feature of our design, but that do not use it in the manner later discussed, are U.S. Pat. No. 4,809,975 (1989) that employs an end weight that slides outward against a spring on a shaft when swung, and U.S. Pat. No. 4,969,921 (1990) whereby a weight slides outward against a spring inside a hollow shaft. Both of these inventions use a coiled compression spring to cushion the weight as it slides outward due to the centifugal force manufactured by the swing.
While all of the above inventions, and others of an ancillary nature not discussed herein, do assist in exercising and conditioning a user's muscles along the swing path, they are all deficient in addressing one important aspect when compared to our present invention, namely the abrupt shock and stress imposed on the muscles at the end of the swing where the fullest articulation occurs.
Full articulation is an important and, desirable aspect of a sports swing for several reasons:
First, full and safe articulation of muscles during a sports swing enables the athlete to maximize the inherent natural capability of his or her physiological body design resulting in optimum performance.
Second, if a sports device can be swung a further distance, the momentum of the device will be increased, thus enabling the device to propel an object a greater distance.
Thirdly, by distributing the effects of the sports swing over a fuller range of muscle movement through stretching, the chance for injury to any particular muscle or muscle group is reduced.
The benefits of adequate stretching before and after athletic competition are well-documented in popular and professional literature, as per these and other references:
1. "Flex Time--Once Ignored, flexibility is now considered essential to fitness," AMERICAN HEALTH, April 1993, Pgs. 68-73. PA0 2. "Treating and Preventing Little League Elbow," THE PHYSICIAN AND SPORTS MEDICINE, March 1994, Pgs. 54-66. PA0 3. "Ahead of the Game--Best-ever workout tips, Tactics and equipment for the weekend athlete," MEN'S HEALTH, April 1994, Pgs. 44-49. PA0 4. "Flexibility--Bend to Get Big," MUSCLE & FITNESS, June 1994, Pgs. 99-101. PA0 5. "Full Back Stretches Relieve Pain," MUSCLE & FITNESS, October 1994, Pgs. 250-252.